Chronic catastrophic data loss with Lion & servers

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Level 1

17 points

Chronic catastrophic data loss with Lion & servers

Auto-save and versions, when combined with multiple users and a server environment virtually guarantees catastrophic data loss.

Here's how you replicate it.

(1) Place a photo on a server.

For us, this is where we recommend people keep important files. Their desktop may be backed up with time machine, but the server is RAID 6 with hot spares, and on top of that is backed up every night. Much, much safer.

(2) Open that photo in preview. Crop it so that you can print it. Close preview. Notice it didn't ask you if you wanted to save?

(3) Open that file again. It's still cropped. The original? Gone. Choose "Revert to Saved" from the file menu. Notice the large number of empty windows on the right? Yup, you can't get back to the prior version, even though you never saved.

Now, as a network administrator, imagine the consequences of this for your network. Users accessing shared files and making changes they need, but not saving them because they don't need to be saved. Yup, their version is now THE definitive version for the entire network.

The ability to do non-destructive edits is something that computer users have been doing since, well, the dawn of computing more or less. Lion removes this. Now, add on top of that user mistakes in a network environment. User accidentally deletes all the text from a 24 page document. They don't know what to do so they close the app. Unless the backup has run since that 24 page document was created, it's gone. Forever. And ever. Amen.

Go to backups you say? What if the document isn't accessed for six months from when the user accidentally wiped it out. Hope your backup server is petabyte big, because otherwise that data is gone.

This is a huge, huge problem.

Joel

iMac, Mac OS X (10.7), Tested on both Server 10.6 and 10.7

Posted on Jul 29, 2011 4:19 PM

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Answer 1

Jul 29, 2011 4:42 PM in response to mythrenegade

Thank you for the warning.

Have you reported this to Apple via the bug reporting system?

Sign up as a developer (for free) at - http://developer.apple.com/programs/register/

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Answer 2

Linc Davis

Level 10

209,739 points

Jul 29, 2011 4:57 PM in response to John Kitchen

Have you reported this to Apple via the bug reporting system?

It's not a bug. It's the intended behavior.

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Answer 3

Badunit

Level 7

30,348 points

Jul 29, 2011 5:27 PM in response to Linc Davis

Yeah, I'm not sure they thought it all the way through. I'm all for versioning (so you can go back to an older verison) and auto-saving (so you don't lose your work if there is a crash) but it seems like the definitive version of the document needs to be determined by the user choosing to save the changes as final (or not). I often make changes to documents (what-if scenarios in spreadsheets, cropping/resizing of images, etc.) and don't want to save them. It is a step in the wrong direction to have to Revert to Saved before closing a file or having to Duplicate a file after opening it just so you can make a temporary change. Makes it much more error prone, not easier and foolproof.

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Answer 4

Jul 30, 2011 4:07 PM in response to Linc Davis

Linc Davis wrote:

Have you reported this to Apple via the bug reporting system?

It's not a bug. It's the intended behavior.

The system is also for reporting enhancement requests, not just bugs.

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Answer 5

Linc Davis

Level 10

209,739 points

Jul 30, 2011 4:42 PM in response to John Kitchen

That's true, but what kind of enhancement would the OP be requesting? CoreStorage is a fundamental shift in the design of the Mac OS. That change is not going to be reversed.

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Answer 6

etresoft

Level 9

56,290 points

Jul 30, 2011 6:18 PM in response to mythrenegade

Don't you have any controls in place to prevent random people from changing files on the server? There is nothing to prevent someone on Snow Leopard from doing the same thing if anyone can save a document. Plus, any document over two weeks old would pop-up a big "locked" dialog if the user tried to modify it in Lion. You wouldn't get that before. And why do you have Time Machine on the desktop instead of on the Server? It seems like it would more handy there.

You are the network administrator. Disable Preview and get your users a decent image editor.

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Answer 7

Jul 30, 2011 7:34 PM in response to mythrenegade

The Versions feature is absolutely not appropriate for use in a multi-user context. I find it hard to believe that any competent administrator would 1) upgrade clients to Lion this soon after release and 2) have versions enabled on shared disk.

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Answer 8

etresoft

Level 9

56,290 points

Jul 31, 2011 6:49 AM in response to bitpuddle

1) There is no evidence that the original poster has actully upgraded any client or is a network administrator.

2) Version is a feature of Lion, not the network. The scenario described by the original poster could occur on any non-HFS+ disk.

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Answer 9

mythrenegade Author

Level 1

17 points

Aug 1, 2011 8:25 AM in response to mythrenegade

I am not an idiot. The very reason we are reporting this is that we are testing this and discovered it. It is not about "random people" changing things on the server. People with appropriate access can do catastrophic damage without even realizing it. Yes, I have also reported this via the Lion feedback.

Let me address some of the comments here:

> There is nothing to prevent someone on Snow Leopard from doing the same thing if anyone can save a document.

That's the problem. Nobody has to actually save to wipe data out with Lion. Versions _does not work_ on server volumes. I have tested this with Lion client and 10.6 server and 10.7 server. Same result. Massive data loss.

> Plus, any document over two weeks old would pop-up a big "locked" dialog if the user tried to modify it in Lion. You wouldn't get that before.

Great. Documents can only be inadvertently destroyed for two weeks. Not sure how this makes anything better.

>And why do you have Time Machine on the desktop instead of on the Server? It seems like it would more handy there.

The server is backed up, as are the clients. It's irrelevant to the problem being reported.

>You are the network administrator. Disable Preview and get your users a decent image editor.

Great idea! Until Photoshop supports versions. Microsoft has announced support for versions with office. I guess we'll have to disable that as well. Maybe we should try to fix the actual problem rather than just disabling software that used to work perfectly and moving on...

> The Versions feature is absolutely not appropriate for use in a multi-user context.

I agree. So do mac users stop using servers now? Doesn't seem like a good option.

> I find it hard to believe that any competent administrator would 1) upgrade clients to Lion this soon after release

I have no clients except my own on Lion at this point, for testing. This is exactly the kind of problem I need to trace down before I deal with huge issues from my users. Also, what happens when we buy new machines? Lion only...

> and 2) have versions enabled on shared disk.

We can turn off versions on a shared disk? I do not see any way to do this. Please enlighten me!

> 1) There is no evidence that the original poster has actully upgraded any client or is a network administrator.

I am a network administrator. This only happens with Lion and versions. I have tested this problem against both 10.6 server and 10.7 server. It exists on either.

> 2) Version is a feature of Lion, not the network. The scenario described by the original poster could occur on any non-HFS+ disk.

The problem is that versions _does not work_ on an AFP server, but acts as if it does. When you use "revert to save" you find that there are no versions. Not good...

Joel

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Answer 10

Aug 1, 2011 10:19 AM in response to mythrenegade

In a group environment where many diferent people

work on one "document" and this is a normal situation,

the there should have been a much more robust control

system in place to begin with. CVS comes to mind, but

there are many other tools out there, many of which are

free and open source. But all of them have some sort

of check-out/commit/revision recovery system.

If anyone can just come in and change things without any

sort of control, then I don't care what the OS is or does, it is just

an accident waiting to happen.

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Answer 11

Linc Davis

Level 10

209,739 points

Aug 1, 2011 10:30 AM in response to mythrenegade

Why are you allowing different people to edit shared files directly on the server? That makes no sense, with or without Versions. Users should check out a copy of the file, edit it locally, and check it back in. That's what the CoreStorage model assumes you'll do. If you try to stick with old habits, you'll have nothing but grief from now on.

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Answer 12

Aug 1, 2011 10:48 AM in response to Linc Davis

So you presuppose that non-it people even know what version control is ? how optimistic.

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Answer 13

Linc Davis

Level 10

209,739 points

Aug 1, 2011 1:23 PM in response to Andy Vandenberghe

So you presuppose that non-it people even know what version control is ?

No. I presume the OP knows what it is.

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Answer 14

mythrenegade Author

Level 1

17 points

Aug 1, 2011 1:32 PM in response to mythrenegade

I'm aware of version control, but I can count on one hand the number of people in this orgainzation who would have any idea of what that is and how it should work. The simple fact is that it's not going to happen. Regardless of what your opinion of our policies may be, we have a lot of users who can edit documents on the server as necessary. For many years it was our recommended place to store ALL of a user's documents because it was far simpler to backup the server than every client machine. With time machine in place we now backup both, but that doesn't change the fact that there are a lot of collaborative documents stored on our server, as they should be.

Lion introduces an unacceptable level of risk. In case you don't understand how data is being lost, I recommend you view the screen capture I created here. This illustrates the problem rather vividly.

Joel

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Answer 15

Linc Davis

Level 10

209,739 points

Aug 1, 2011 1:48 PM in response to mythrenegade

Before Lion, you were just lucky that you didn't have unintended changes to shared files all the time. Now your luck has run out. If you're bitterly determined to keep doing things the same strange way you've always done them, then you should start planning to migrate off the Mac platform. It no longer suits your needs.

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